1. Field of the Invention
The present invention relates generally to the reduction of bone fractures and other bone conditions and pertains, more specifically, to instruments and techniques which allow such reduction to be accomplished with minimally invasive procedures. In particular, the instruments and techniques are used to manage bone fractures and bone conditions located near joints of the body (peri-articular fractures) and fractures that involve joint surfaces (intra-articular fractures).
2. Description of Related Art
Most joint related fractures require precise reduction and stabilization so as to avoid healing with a rough or misaligned joint surface which quickly can cause disabling post-traumatic arthritis. The majority of these intra-articular fractures currently are reduced under direct inspection of the bone fracture fragments, utilizing relatively large incisions to gain open access to the injured areas. The incisions extend into the joint and are carried through muscles, tendons and capsules in order to reach the fracture. Once exposed, the bone fracture fragments are physically disengaged from their displaced positions and are reduced as anatomically as possible, all under direct vision. These fragments then are fixed in the reduced position, as by wires, screws, plates and external fixators used either alone or in various combinations. Despite careful operative procedures, such open reduction carries substantial risks to the patient, ranging from soft tissue necrosis to deep wound and joint infections. Even where incisions heal well, scarring of the transected tissues is inevitable and can result in joint stiffness and potentially serious functional restrictions affecting daily living, as well as work and recreational pursuits.
More recent attempts at avoiding the drawbacks and risks of open reduction have involved techniques for the percutaneous reduction and affixation of bone fracture fragments, utilizing small cylindrical and flat-ended bone punches and pins inserted through relatively small soft tissue incisions and fracture gaps or even drill holes. Under arthroscopic or radiographic visualization, these instruments are used to manipulate bone fracture fragments into more anatomical positions where the fragments are stabilized with screws, plates or a combination of both screws and plates. Although these techniques can avoid some of the complications afflicting open reduction, to date such techniques have been successful only in the reduction of simple fractures, such as splits and some depressions.
The utilization of bone punches for the reduction and stabilization of bone fractures presents crucial shortcomings. Thus, bone punches permit only unidirectional motion and concomitant unidirectional movement of bone fracture fragments. Further, bone punches have relatively small contact, or working surfaces with which to engage bone fragments, usually no more than one square centimeter. As a result, when attempting to reduce bone fracture fragments, and especially comminuted bone fracture fragments, rather than pushing the bone fracture fragments into a desired position, bone punches tend to slide through gaps between the bone fracture fragments and penetrate into the joint itself, rendering the punches ineffectual and even potentially harmful to the joint. Larger diameter punches would require corresponding larger diameter bone openings for enabling introduction of the punches, presenting a danger of developing stress fractures at the level of the entry holes, such stress fractures being an unacceptable condition.